Department store machine



March 15, 1938. F, L. FULLER ET AL DEPARTNENT STORE MACHINE Filed Dec. 4, 1935 ll Sheets-Sheet 1 Y E N R O T T A March 15, 1938.

F. L. FULLER ET AL DEPARTMENT STORE MACHINE Filed Dec. 4, 1935 ll Sheets-Sheet 2 N2 .m N New .8m .8

TTORNEY Filed Dec. 4, 1935 ll Sheets-Sheet S A ATTORNEY 11 Sheets-Sheet 4 F. L FULLER ET AL DEPARTMENT STORE MACHINE Filed Dec. 4, 1935 March 15, 1938.

March 15, 1938. ER ET AL 2,110,854

DEPARTMENT STORE MACHINE Filed Dec. 4, 1935 ll Sheets-Sheet 5 ,INEENTZ? Mi 9. XXX

' A'i'ToRNEY Filed Dec. 4, 1955 11 Sheets-Sheet 6 ATTORNEY M 1938- F. L. FULLER ET AL 2,110,854

DEPARTMENT STORE MACHINE Filed Dec. 4, 1935 ll Sheets-Sheet 7 INV N. I06! fi ATTORNEY March 15, 1938- I F. L. FULLER ET AL 2,110,854

DEPARTMENT STORE MACHINE Filed Dec. 4, 19:55 11 Sheets-Sheet a F I612. M g T/,-- W J n on n nInn no n In "In I mu r9 2 II "I i i I 2:" ..I I 1 gm 1251a 00 I 2/ M 5 I 3 M i I 0 H00! nn FIG.13.

INTERNATIONAL STORES INC.

SOLD T0 om: g2; oA-r:

' ATTORNEY moum' March 15, 1938. F. FULLER ET AL V DEPARTMENT STORE MACHINE Filed Dec. 4, 1935 11 Sheets-Sheet l0 FIG. 21

PIC-3.20.

5: 2w BY March 15, 1938. ER ET AL 2,110,854

DEPARTMENT STORE MACHINE Filed Dec. 4, 1955 ll Sheets-Sheet ll mwnewr m man/w C4 Jun- Am a;

a "WPWS WA4rru=-------- mm rmm mmvmkwma a- 1mm Mfr ATTORNEY Patented Mar. 15, 1938 DEPARTMENT STORE MACHINE Frederick L. Fuller and George F. Daly.'West- Orange, N. 1., assignors to International Business Machines Corp, New York, N. Y., a corporatlon oi New York Application December 4, 1935, Serial No. 52,766

17 Claims.

This case relates to recording machines.

In particular. the invention deals with a machine ior recordingsales transactions in large stores such as department stores. The sales transaction is recorded b the machine on a sales slip or the like in the form of a printed record. and is also recorded one tabulating card in the iorm of a punched coded record. The printed sales slip is usually given to the customer, while the punched card is retained in the store and subsequently used to control tabulating machines ior tabulating the information on the card.

Broadly, the inventionhas for its object to provide a novel, improved, machine for recording data pertaining to the article sold, to the clerk making the sale, and to the customer.

More specifically. an object oi the invention is to provide novel card periorating means, and in such means to provide a novel punch pin guide and holder.

Another object is to provide a new key-controlled mechanism to enter an item in diiierentially operable means, such as item indicating elements. type members, or punching members.

25 Still another object is to provide a novel iorm oi item designation on a record medium, such as a slug, token. or check, and further to provide novel sensing means .ior reading the item designation and transferring the value denoted by the 30 designation to printing and punching means.

It is also an object to provide novel means for transferring the setting of punching means to other recording means, such as type wheels.

Other objects are to provide novel card eject- 35 lng means and novel positioning means for the sales slip.

Still other objects will appear in the following parts of the specification and'irom the drawings, in which:

' 40 Fig. 1 is a plan section through the machine;

; Figs. 2 to 6 are respectively sections along lines I to t oi Fig. l;

' Fig. 6a is a detail oi an item wheel on a punch slide with the item wheel in section;

Figs. 7 and 8 are sections along lines I-1 and -4 oi Fig. 1, respectively; I

Fig. 9 is a section along lines t-l oi Fig. 3;

Fig. 10 is a section along lines Il -it oi Fig. 1;

Fig. 11 is a section along lines, il'ii of Fig. 1;

Fig. 12 shows the tabulating cards punched in the machine;

Hg. 13 shows a sales slip on which a record is printed on the machine;

Fig. ,14 shows the customer's account number token;

Fig. 15 shows the token representing the kind oi article sold;

Fig. 16 is a section along lines it -it oi Fig. 2;

Fig. 1''! is a section along -lines ll-il of Fig. 2;

Fig. 18 is a detail section taken along lines l8ll oi Fig. 1;

Fig. 19 is a plan view oi the punching mechanism oi the machine with covering parts removed to expose interior mechanism;

Fig. 20 is a detail, end, view of a punch slide, the punch carried thereby, a stripper bar. and part of the punch operating or pressure plate;

Fig. 21 is a section on lines Ii-li of mg. 20;

Fig. 22 is the timing diagram, and

Fig. 23 is a perspective view of the machine.

Following is the list 01 items which may be recorded for each article sold and the number oi denominational orders assigned to each item. To each denominational order of an item. one card column is assigned.

columns Price 01' one article-maximum $9999.99"--- 6 Transaction (cash take. cash carry, charge take, charge carry) 1 Sales clerk 2 Customer's account number 6 Department to which the machine is assigned. 2 Kind oi article 3 Date (day-2 cols., month-2 cols.) 4

Total 24 For illustration, the Hollerith code of punching a card is used. This code employs a single perforation in one of the index point positions of a card column to designate a number. Thus numbers 9, 8, 7-0 are designated by a single perioration in one oi positions 9 to 0 01 a card column (Fig. 12).

Briefly, the manner in which a sale is recorded is as follows: The clerk writes on sales slip S (Fig. 13) the name and address and other supplementary information relating to the sale. For convenience. when the clerk writes on the slip the supplementary iniormation referred to above. he may through a carbon sheet simultaneously inscribe this information on the blank portion oi the first card to be punched. Each slip has space at the bottom to receive three lines s of printed data, each line relating to the sale or a separate one oi several articles sold to one customer. Three is considered the usual maximum number of articles sold to one customer in one store department. I! it is desired to record more than three sales on one slip, a longer sales slip may be provided.

For each printed line 01' data on the slip 8. one card T (Fig. 12) is punched. For three articles and three lines oi printed data on one sales slip, three cards arepunclied,

The date and department items are pro-set in the machine. The kind oi article and the customer's account number are represented respec-- tively by tokens G and P (Figs. 14 and 15) bearing identifying configurations. These tokens are inserted in the machine to control the setting of the punching and printing means for recording the kind of article and the customer's charge account number. A ten key board is operated to set up the amount or price, the kind of sale, and rerks number. A sales slip S is placed in printing position. These three steps, namely: token insertion, key operation, and sales slip positioning, may be carried out in any order. After these three steps have been taken, the operator inserts a card T in the punch section. This insertion unlocks a manual actuator for a cycle of operation.

During this cycle, the card is punched and ejected and the first line s of data is printed on the sales slip. Should it be required to record more than one sale on the same slip, the slip is re-positioned, and the clerk sets up on the keys 8 new amount and repeats the setting up of the keys for the kind of sale and clerk's number. A second card is inserted and a second cycle of the actuator eifected, resulting in punching the second card with the data of the second sale and in printing the second line s on the sales slip.

A detail description of the machine follows:

There are twenty-four punch slides or carriers I0 (Figs. 1. 2. 3, and 19) one for each card column to be perforated. Each slide I2 is a narrow elonga ed bar slotted longitudinally to provide a card receiving slot II (Figs. 6, 8, and 20). Each slide holds one punch pin I2. These punch pins are narrow, rectangular, in cross-section and perforate elongated rectangular holes in the card.

. The punch pins must be smoothly and accurately mounted in their guiding holes and must be capable of moving accurately into their die holes. It is difficult to bore and accurately machine and finish an internal, rectangular-shaped, elongated, punch guiding and receiving hole. The following means and method have been devised to overcome the above difficulty and to provide a smooth, accurate, guiding aperture and die hole for the punch.

Referring to Figs. 20 and 21, one side of the slide I0 is milled above and below slot II with an open, angular, channel for accommodating half the cross-section of a punch pin I2. This open channel is accurately finished. A pair of plates I2 and I2 are also milled with open, angular, channels which are finished accurately and of dimensions to accommodate half the cross-section of the punch pin. Plate I2 is then welded to the slide above slot II and plate I2 welded to the slide below slot I I with the channels in the plates and slide facing each other to form rectangular apertures above and below slot I I for mounting and guiding a punch pin I2. The slide and plate I2 thus provide an upper punch holder and guide and the slide and plate I2 provide a lower punch The twenty-four slides or punch pin carriers II are arranged in parallel vertical planes and are slidably guided for horizontal movement within their own planes by the slots of upper and lower comb bars I2 and by the surfaces of cross bars I2 to which the comb bars are secured. These cross bars are suitably held in rigid relation to the vertical frame plates I1 and I2 carried by base plate I2. The portions of the slides adjoining card-receiving slots II ride along comb bars a and 2| (see m. a), which thereby assist combs I2 and bars I2 in restricting the carriers to slidable movement in their own planes. At the same time, the confronting vertical sides 0! comb 22".

22 and 2| serve as side guides for the card T to assist in locating the card properly when the card is inserted through slots II into punching position. The card is inserted lengthwise so that when in punching position, each of its columns is in the plane of one punch slide in position to be perforated by the punch mounted by the slide.

Each of the punch slides is separately adjustable lengthwise to one of ten positions to bring the punch I2 above one of the index point positions 9 to 0 of the card column in line with the slide. The punch pin I2 is provided, near its upper end, with a transversely extending button 22 resting on a rail 22 and by this engagement, the rail normally holds the punch pin above card slot II and clear of the card in punching position. There is one rail 22 for each punch and the rails are arranged similarly to the punch slides so that during movement of a slide to a difiierential position. the punch moves between a pair of rails with its button 22 riding on top of one of the rails.

Rails 22 are secured at opposite ends between the locating teeth of a pair of transversely extending combbars 22 .and 22. To the upper surfaces of the latter bars is secured a horizontal plate 22 which covers all the possible differential positions to which the twenty-four punches may be adjusted. Rails 22, bars 22 and 25, and plate 22 form a rigid punch operating assembly of which rails 22 constitute punch pin guiding and restoring or stripping means and plate 22, the punch pin depressing means.

Bars 22 and 22 of the punch operating assemblyare formed at each end with reduced circular portions seated in slots 21 (Fig. 5) of pairs of levers 22 and 22, one pair at each side of the punch operating assembly. Levers 22 and 22 are pivotally connected to each other at their adjacent ends and pivoted intermediately on studs 20 extending from the vertical side frames I1 and I2.

Levers 22 are connected to depending links 2| (Figs. 5, 8, 19), formed at their lower ends with vertically elongated slots 2| (see particularly Figs 5 and 8). A lever 22 is secured to the right hand end of a shaft 22 (as viewed in Fig. 1). Shaft 22 is journaled by frame plates I1 and I2, and at its left end, the shaft rigidly carries an arm 22' parallel to arm 22a of lever 22. Arms 22a and 22 are provided with pins 222 which extend into slots 2 I of links 2 I. At their outer ends, arms 22 and 22 have pins 22I extending into slots 222 formed in the sides of a ball 22 freely pivoted on a rod 22 carried by frames I1 and II. The sides of ball 22 are connected by cross bar 22 extending above all the slides I0 and adapted to engage in any of ten spaced notches 21 formed along the upper edge of each slide.

When the slides have been variously set in one of their ten difierential positions, a cam 22 on cam shaft 22 (see Figs. 1, 3, and 5) acts on arm 22b of lever 22, to rock the lever and its shaft 22 clockwise (Fig. 5). The first portion of the movement of shaft 22 causes arms 22a and 22' to rock ball 22 downwardly by camming coaction of pins 22I with the upper, inclined, portions of slots 222. The ball 22 is moved down to dotted line position, Fig. 5, and bar 22 is thereby moved into roughly alined notches 21 of the twenty-four slides II. When bar 22 is fully seated in these notches 21, it alines the notches perfectly, and thereby locks all slides I2 accurately, with each slide occupying the exact differential position for which it had been adjusted. Subsequent to this action of bar 22, as shaft 22 continues its clockwise move- As a result, levers 22 and 2! depress. the-punch operating assembly. Plate 22 of the assembly thereupon engages the heads of all twenty-four punches i2, and presses them through the selected index point positions of the card T in punching position.

While arms 82a and 32' are depressing the punch assembly, pins I which have cleared the inclined, upper portions of slots 222, travel along edges 32! slots 32!. These edges are concentric about shaft 22 when ball 24 is in dotted line position, Fig. 5, so that movement of pins 22! along these :edges does not tend to' move the ball, but serves to hold the bailin contact with limitstop pins 824.

When depression of the punch assembly,

and. consequently, the punching of the card, is'

completed, a cam II on shaft 20, complementary to cam 3!, acts on am 220 of lever 22 to rock the latter counterclockwise (Hg. During the first part of this movement, pins 22' rise ldly along slots 2| of links 2|, and pins I2lmove idly along edges 32! of ball 34. Before the pins I2l leave edges 22!, pins 220 engage the upper ends of slots 3|" and startelevating links 2|.

This action of the linksraises the punch operating assembly, and during the rise of the assembll'. its restoring or stripping bars'fl engage buttons 22 of the punches to lift the latter, thus stripping the punches from the card and restoring them to initial, raised, positions.

When the punch pins have been lifted clear of the card, pins 32f move into the inclined portions of slots 222 of bail I4 and start rocking the bail clockwise (Fig. 5). Thus, during thelatter portion of the punch restoring action, ball 24 is rocked in a direction to release locking bar 26 irom notches ll of the slides. which are thus left free to be restored. The timingof the above punching and locking actions will be more specifically given in, the

The manner in which slides II are moved lengthwise to be set diiferentially' will now be explained. Each slide II is individually adjust- I able to set its punch i2 in one of ten differential positions 0 to 9. In the initial position of a slide, at the right end 'of its travel, as viewed in 'Figs. Band 8, the slide isin 0" position. From this latter position, it may move one to nine steps to the left to set its punch II at succes-, sive positions "1 to 9" for perforating the cor- I 1 responding 1 toil index point positions oi a card column.

For convenience, in the following parts of the description and in the drawings, the common reference character for similar elements may be suilixed by a distinguishing character to indicate the item to which the element relates. Distinguishing characters 9, a, b, d, a, t, and c will be used to denote respectively elements related to purchaser's account number, kind of goods,

slides Illa, four date slides lid, six amount slides Ila, one transaction slide Hit, and two clerk number slides lie.

.or' record member of which short slot, 2 by a Date and deportmentset'tino Referring to Figs. 2 and 23, housing 40 of the machine has an opening at the top which is closed by a hinged door 4i located above cogtoothed wheels 42 (Figs. 1, 5, and 1'1). The four wheels 42 at the left correspond to thetens and units of days and tens and units of months;

. the next three wheels 42 correspond to thekind of goods; the two following wheels correspond to thetens and units of the department number; and the last six correspond to'the account number. The door 4| is opened to provide access to the wheels 42 and at the beginning oi each day, the operator manually sets day wheels 42. At the beginning of each month, the month wheels 42 are set. The department wheels 42 are set when the machine is assigned to record sales in a certain store department. Each oi these wheels 42'has its teeth meshed with the teeth of type wheels rotatably carried on a shaft (see also 1, 5, and 1'7).

There are ten teeth on each type wheel 42,

cach' tooth faced with a type legend Oto 9 for with rack teeth 41 formed along the upper edge.

of a punch slide it. The four date wheels 42 are thus geared to the four dateslides lldfthe three kind of goods wheels 42 are geared to slides lilo, the department wheels 42 are geared to slides lib, and the account wheels 42 are geared to the six slides lllp.

When the date and, department wheels 42 are adjusted, through connected gear wheels 46 meshed with teeth 41 of the corresponding punch slides, they advance the latter slides to position their punches for perforating the date and department columns of a card with the coded designations of the date and department items.

'At the same time adjustment of the date and department wheels 42 sets the meshed type wheels 42d and 43b (see Fig. '17) to print the date and department data.

The control of the account number and kind of goods slides Hip and, q and the corresponding type wheels 43 by tokens P and G will now be explained.

Token. setting Token P, and G shown in Figs. 14 and 15 are preferably made of metal, though they may also be made of any ot er suitable material such as still paper, hard rubber, or composition material.

The token may also be referred to as a check. slug. it is the equivalent. To represent a digit on the token, the latter is formed with a vertical slot 42 proportional in length to the value of the digit. Thus "0" is represented by a slot of zero length or asolid portion of the token, 1" is represented by a slot twice the length of the 1" slot, and so on, the slot representing 9" being the longest. Each denominational order oi the number designatedby the token is represented in a diflerent vertical portion orthe token, as indicated in Figs. 14 and 15. Each token also has a horizontal slot 40 near the bottom which is located eccentrically to the vertical center line of the token. Rigidiy secured to frame plate i1 is a frame Bl (see Figs. 1. 8, and 18) constructed to provide a pair of separated pockets or receptacles ii and I! to respectively receive tokens P and G. The lengths of the pockets are the same but their widths differ to correspond to the different widths of the two tokens. The top of housing 4| is cut out to permit insertion through the housing of the tokens into their respective pockets ii and 52. When a token is fully inserted in its pocket, its lower edge engages the top of a vertically slidable member 53 and depresses the latter against resistance of a spring N. The spring connects member 53 to a pivoted latch lever ll which has a lug 56 engaged with the advanced portion 51 of the front edge of member 33 when the latter is in upper position There are two such members 53 and companion latches ll, one member and latch for each of pockets If and It.

When a member is depressed by insertion of a token, its front edge portion 51 rides of! lug it of the companion latch I permitting spring N to rock the latch anticlockwise (Fig. 8) to move the tooth ii at its upper end into slot 4! of the token. This locks the token in correct position in its pocket.

A token must be inserted with the front face, seen in Figs. 14 and 15 towards the operator.

positioned at the front of the machine (see Fig.

23 in order to bring the several columns or orders of designation slots into proper correlation with the denominational order mechanism for reading these slots. By locating the locking slot ll of a token oi! center, the operator is compelled to insert the token correctly otherwise the locking slot will be out of line with the tooth N of latch I and not in position to receive the locking tooth, in which case, as soon as the clerk relieved the pressure of his fingers on the token, member I would be raised by spring 4 to eject the token to inactive position.

The reading means for the token designations comprises the six account number punch slides lop and the three kind of goods punch slides liq. These slides are formed at their forward. left hand ends (Fig. 8) with steps I arranged in echelon, one behind another, and at different distances from the longitudinal center line of the slide. The values corresponding to the different steps I! are indicated alongside the steps. The extreme forward edge of the slide represents value 0.

Each of slides lip and a, as well as the price, transaction, and clerk number slides its, t, and c has a pin and slot connection at its rear end with the upper end of an arm II. The several arms I are freely pivoted on a rod Ii carried between frame plates i1 and il. Each arm II is separately connected to a spring 62. The springs urge the arms 60 and connected slides towards the left (Figs. 6 and 8). Initially, the arms cannot move to the left because they are held back by engagement with a common bar 33 secured to the upper ends of arms 84 and 84', rotatabiy mounted on rod I (see also Fig. 3). The department and date slides are not connected to arms I, leaving room below the latter slides for locating arms 34 and N. The arm 34' is pinned to a link OI (Figs. 3 and 6) which is forked at the rear to slidably receive cam shaft 38. Link I! has a follower roller '8' riding on cam 68 of cam shaft 3|. In home positions of shaft 33 and cam it, the

roller is on a high dwell portion of the cam so that link 5, cross bar 63, and arms II are held at their right hand limits (Figs. 6 and 8). Slides llp, a, a, t, and 0 connected to arms I are therefore initially maintained in 0" positions.

When cam shaft 39 is rotated, counterclockwise, (Fig. 6) by means to be described further on, roller 66 rides on the dwell portion of cam 00 and along a drop of the cam. Under the influence of springs 62, arms iii move counter-clockwise (Fig. 6) and through engagement with ball bar 63 rock the latter in the same direction, causing link i to move to the left and its roller 3! to follow the contour of cam I. Arms ll move under the influence of their individual springs 02 and correspondingly move their connected slides until the latter are arrested differentially.

When the sale is for cash, a charge account token P is not inserted in the pocket Ii and similarly when it is not necessary to record the kind of merchandise, token G is not inserted in its pocket 2. When a token is not inserted, it is required to maintain its reading, punch, slides in their 0 positions. This is done as follows: In the absence of a token from its pocket, the associated member 83 is in upper position and its high or advanced portion 51 is engaging ing it of associated latch ll to maintain the latter at its clockwise limit (Fig. 8). Latch has a pin and slot connection with one of two bell crank levers I, there being one such lever for each latch. The upper end of each lever 01 is formed with a transversely bent ing 01' extending across the group of token reading and punch slides Ila or 9. When a latch I5 is in clockwise, non-locking position, through its connection with a lever I! it holds the latter at its counterclockwise limit in which the stop lug 01' of the lever is in front of steps "-0 of the group of associated punch slides llp or a. When so positioned, the stop lug ll' will arrest advance of the slides before they have moved more than a slight amount from their "0" positions. When the slides are later alined by bar ll, in the manner previously explained, they are set accurately in "0" positions.

In above manner, the absence of a token G from pocket 52 results in slides ila being held in their 0 positions, while the absence of a token P from pocket ll causes slides ilp to remain in "0" positions.

When a token is inserted, the associated latch ll rocks anticlockwise (Fig. 8) to move its tooth ll into notch ll of the token, locking the latter in its pocket. As a latch rocks anticlockwise, it moves connected lever 31 clockwise to lower stop lug ll' out of the path of advance of the associated slides II. The latter may now move to read tokens P and G.

Under the influence of the springs 3!, arms ll connected to slides lip and a move towards tokens P and G in pockets Ii and 82. If a token has a solid "0 designating portion in front of a punch slide, the slide will be arrested when its front edge engages the token and will be set in 0 position. If the token has a vertical, item designating slot 0 equivalent to value 1, 2, 3-8, or 9 in front of the slide, the latter will move into the slot until the step '3 corresponding to the length of the slot engages the solid portion of the token above or below the slot. Thus, slots 43 of lengths 1, 2, 3, or 4 permit the slide to move 1, 2, 3, or 4 differential distances and arrest the slide when its step "-1, 2, 3, or 4 engages the part of the token above the slot. Slots ll of lengths equivalent to 5, 6, 7, 8, or 9 arrest the slide after the latter has moved 5 to 9 differential distances by engagement of steps "-5 to 9 with thepart of the token below the slot.

As the slides Ito and advance 1 to 9 differ- 5 ential distances, their pimches I! move to corresponding positions for punching the i to 9 index point positions of the account number and kind of goods columns of a tabulating card.

Further, as slides Ito and a move forward to their diflerential positions under control of tokens P and 0. their rack teeth 41 coact with the meshed toothed wheels 4' of nested shafts 45 to turn these shafts correspondingly to the movement of the slides (see Figs. 1, 8, and i7). Cog- 16 toothed wheels 42 of these shafts l5 meshed with toothedtype wheels p and o and set the latter for printing the account number and the kind of goods data corresponding to the setting of the slidu llpand a. 90 During the final portion of the cycle of shaft 8l,,ca'm ll acts on roller II to move link I to the right which causes bail bar t! to rock clockwise and pick up the variously positioned arms I and return them and their connected slides to as their "0" positions. Blides lip and 0 thereby withdraw from tokens P and G.

After slides lip and a are restored. a cam it (see Figs. 2. 3, 6, and 8) on shaft I rides past the lower, nose end of a lever II and rocks the so latter clockwise. lever N is connected to a link II which has a transversely extending pin II passing through alined slots 12 of the two latches ll. ,When lever It is rocked clockwise, through link It and pin II it moves latches II in the same as direction, releasing teeth II from slots it of the tokens. The retraction of the latches again places stop lugs ll of levers |l in front of the "9" stops ll of slides llp ands. At the same time,'springs It raise members to partially eject the tokens, 40 which then protrude above the top of housing 40 to be conveniently removed by the operator.

The setting of the nine remaining punch slides; I. e., the amount, transaction, and clerk number punch slides Ilo. t. and c and the corresponding 4.1 typewheels iseflectedundercontrolofaten key keyboard. as will now be explained.

Tenm control There are ten keys ll, one for each of digits 0 so to9;asshowninl'lgs; l and23. Thesekeysare mounted for vertical movement in the frame (see l'igA) andtheirstemsarebenttransversely,as

shown in Fig. 2 to place their lower portions in parallel planes, side by side.

5.. The disposition of the various key stems is indicated at the bottom of Fig. 2 by the digital values to which the stems and keys correspond. The lower ends of the key stems are located side by side, in horizontal, transverse alinement, and

to pivotailyconnected to the horizontal arms of bell crank levers ll freely pivoted on a shaft 11. The vertical arms of levers It terminate in horisontally alinednose portions II, each in front of one of ten stop fingers ll. These stop flnsers are as riaidlymountedonashaftllandarrangedwithin the same parallel, spaced, planes as levers It, as indicated in Pig. 2. The fingers ll-are also rotatively displaced about theirshaft II in the order indicated in Hg. 4. Accordingly. each nn- :0 ger ll must move a diiferent distance counterclockwise to reach the nose portion It within its plane.

the left end ofshaft It (as vlewedin Hg. 2) rigidlycarriesapinionllmeshedwithawide geardrumll frsely.r'otatablycarriedbyashaft If. Mashed with the top of drum II are nine toothed item indicating wheels '3. Each wheel 88 has ten teeth marked on their faces with indicating numerals 0' to 9 to be viewed through a sight opening it in the top of casing 40 (see 5 P18. 23).

Indicating wheels 83 are freely A rotatably mounted on a shaft 88 iournaled between frame plates II. It, and 81 (see Fig. 2). The wheels II lie between the spaced sides of an H-shaped car- 10 rlage it (see also Fig. 1). The sides of the carriage,at their front ends. are forked to slidably receive shaft 05. At their rear, the carriage sides are formed with threaded holes for coaction with I the threaded portion of a shaft it.

Carriage it is thus mounted on shafts II and II for slidable movement along the shafts to be advanced by rotation of shaft ll.

Shaft It is rotatably journaled between frame plates II, It, and 81. Rotation of ,shaft 80 through coaction of its threaded portion with the threaded apertures of the carriage effects movement of the carriage along shafts l and II. As the carriage moves along these shafts, it slides wheels It along shaft ll.

In the initial, home, positions of the. parts. the carriage is at the extreme right of its travel (as viewed in Figs. 1 and 2) and the item wheels II are entirely clear of all nine right hand punch slides I Ila, t, and 0. Each step of movement of the carriage to the left (Fig. 1) will move one of wheels 83 out of mesh with drum ti and into mesh with rack teeth 41 of the unit order slide llc. Thus, the first stepof movement of the carriage brings the first wheel "from the left of the carriage mesh the wheels 83 successively with the slides Ila, t, and c. At the end of nine steps of transverse movement of carriage ll, all nine wheels I! will have moved oi! drum ti and into mesh with the nine slides Ila, t, and c.

The transverse movement of carriage II is efl'ected under control of keys It. Each time a key I! is depressed to enter a value in a wheel it, it causes a step of movement of carriage It. Should the keys be depressed nine times to set up the nine wheels, then all nine wheels will be meshed with all nine slides Ila, t, and c. There is onekey operation-required for the kind of sale and two key settings for the clerk's number. When the price of the article is the maximum six denominational order figure, six key operations are required to set the price. Thus. the maximum possible settings are nine. Howso ever, the price may be less than a six order figure, for example, 8.50 in which case only three wheels its will be set in addition to the settins of the one wheel at and the two wheels 88c, making a total of six settings, so that the last three .5 wheels will remain on drum II and will not be muhed with the slides. The other six, key-set,

wheelsllwillbeinmeshwiththeflrstsixslides II from the right (Pig. 1). The three left hand slides II will not be in mesh with any of wheels go The setting of the slides Ila, t, and c is effected to the contrary, the slides Ia not meshed with wheels 00 would move unimpeded to their "9 positions, resulting in a wrong record of the price being punched and printed. To avoid this error, the slides I04 not in mesh with wheels 00 must be restrained irom advancing beyond their 0" positions. For this purpose, the leit leg oi carriage 00 (as viewed in Figs. 1 and 2) is iormed at its iront end with a depending laterally extending finger 00 (see also Fig. 18) which lies in iront oi all nine slides Ila, t, and c when the carriage is in the initial, right hand position.

Finger 00 when in iront oi a slide blocks advance oi the slide beyond its "0" position. When the carriage moves one step to the leit to mesh the first wheel 00 with the first slide, then finger 00 moves away irom the iront oi the first slide. As successive steps oi travel oi the carriage are eiiected to successively mesh the wheels 00 with the slides, the blocking finger is displaced irom in front oi the successively meshed slides. At the end oi nine steps of travel, all nine wheels 00 are meshed with slides I0, and finger 00 is completely displaced to one side oi the slides.

Pinion 00 oi shait and item indicating wheels 00 are both in mesh with gear drum 0|, and are oi equal diameters so that the pinion and wheels move through equal arcs upon rotation oi the drum. Indicating wheels 00 and shait 10 thus have ten corresponding difierential posilons. These ten positions of a wheel 00 are defined by its indicating teeth 0, I, 04 while the corresponding positions oi shait 10 are defined in the same order by stop fingers 10-0, I, 14.

Referring to Fig. 7, shait 02, on which drum H is rotatably mounted, rigidly carries a pinion II (see also Figs. 1 and 2) meshed with a gear 00 rotatably mounted on a shait 04 carried by the irame plates 00 and 01. Rigid with the side oigear00isapinion0lmeshedwithagear sector 00 which is ireely pivoted on a stud 01 carried by irasne plate 00. A spring 00 connected to gear sector 02 urges the gear sector clockwise (Hg. 7). Sector 00 has a travel 0! about and the ratio oi gearing 00, 00, 00, 02, 0I, and 00 is such that the iull stroke movement oi sector 00 is capable oi producing eleven revolutions oi wheels 00, more than sui'ilcient to move each oi the nine indicating wheels 00 through an entire revolution.

Bhait 02 has fixed to it an arm 09 adjacent the aide oi drum II. In the initial position oi the parts, arm 00 is engaging the tree end oi a pawl I00 pivoted to the side oi drum 0| and urged by a spring I00 towards arm 00 and into limiting engagement with a pin IOI extending irom the side oi the drum. When shait 02 is rotated clockwise, its arm 00 ooacts with pawl I00 to rotate drum II in the same direction. During the counterclockwise, restoring, revolutions oi shaft 00, its arm 00 will withdraw irom pawl I00 and at each revolution, the arm will ride wt the pawl, spring I00 yielding to permit the pawl to be cammed aside. Thus, arm 00 and pawl I00 provide a one-way, clockwise, driving connection between shait 02 and drum 0I. Drum H is never moved counterclockwise, as will later be brought out. but is moved only clockwise by the aioresaid one-way driving connection, and under control oi pinion 00 with which it is meshed.

Drum 0I cannot move clockwise unless pinion 00 and its shait 10 are iree to rotate counter clockwise (Figs. 4 and i6). Bhait 10 fixedly carries a disk I0! (see figs. l, 2, and 16) which has ten teeth I00, one oi which is normally in engagement with the nose end I04 oi a bell crank lever I04. Teeth I03 are spaced correspondingly to the spacing oi stop fingers 10 about shait 10. When nose end I04 is engaged with a tooth I00. shait 10 cannot rotate counterclockwise and drum 0| is not iree to be rotated clockwise.

Lever I04 is rotatably carried by shait 11 and is urged counterclockwise (Figs. 4 and 16) to engage its nose end I04 with a tooth oi disk I02. The horizontal arm oi lever I04 is bent angularly to provide a transverse lug I00 extending under the leit hand arm of a bail I01 ireely pivoted on shait 11.

The cross bar I01 oi the bail underlies the lower edges oi the horizontal arms oi all ten bell crank levers 18 which are pinned to the ten keys 10 (see Fig. 4). Spring I00 acting through lever I04 and its lug I00 urges bail bar I01 upwardly to maintain contact with the lower edges of the horizontal arms oi levers 1t and in so doing, the spring helps to iorce keys 1! to their upper positions. The keys are additionally urged to upper positions by springs I00 acting on levers 10.

Riveted to the leit side oi bail I01 is a plate I00 having two sets oi reversely inclined ratchet teeth IIO. Each set of teeth IIO coacts with one oi the end teeth III oi the iull stroke toggle pawl iii. A spring III acting on the pawl holds it set in either clockwise or counterclockwise position.

When any oi the ten keys 1! is depressed, it rocks the connected lever 10 clockwise (Fig. 4) which depresses common bail I01 and the toothed member I00 carried by the bail. Once depression of a key is begun, the key cannot rise again until the iull down stroke has been completed due to restraining coaction between the lower tooth II! oi pawl ill with the lower set of teeth IIO oi member I00. when a iull down oke oi the key is made, then upper oulde ber I00 strikes projection lit oi 1 rocks the pawl counterclockwise. When w; operator releases pressure on the depressed key. springs I00 and I00 combine to force the it: its upper position and during restoration 0! o key, upper tooth III oi pawl Iii engages with the upper set oi ratchet teeth III oi member ill to prevent depression oi the key beiore it has finished its up stroke. Just beiore the end oi the up stroke oi the key and oi bail I01, the lower shoulder II4 oi member I00 strikes lug I II oi the pawl and causes return oi the pawl to initial clockwise position.

At the beginning, all nine item indicatinl wheels 00 are sitting on top oi drum 0i, each wheel at zero position, and correspondingly shait 1B is at zero position with detent I04 engaging a tooth I00 oi disk I02 to prevent rotation oi the shait 10, drum 0|, and wheels 00 under the infiuence oi spring 00.

When any oi the keys is depressed, it actuata the connected lever 10 to place the nose end 10' oi the lever in the path oi rotation oi the stop finger 10 which is in the same plane. Further, when the lever 10 is actuated, it acts on bar M1 to rock bail I01 clockwise (Fig. 4). The ball in turn acts on lug I00 oi bell crank lever It; to rock the lever clockwise, opposed by the pull oi spring I00. As a result, detent end I04 oi lever I04 is released irom the teeth oi disk I02. There is nothing now to restrain rotation by spring actuator 00 oi shait 10. its pinion 00, drum II, wheels 00, gears 02, 00, 00, and 00. Shaft 79 and the other elements oi the above gear train, when released by detent I04, rotate under the iniiuence upstroke of the key, spring III also restores lever I to replace its detent end in the path of rotation of a tooth I" of disk I, thus arresting the supplementary movement of shaft II. The total of the lnitialand supplementary movements of shaft II displaces the shaft through an even multiple of its differential positions. Correspondingly, ite'm wheels I! will have moved through the same number of their differential positions.

For example, depression of the "0" key releases common detent IN from shaft II and moves "0" lever It to place its nose end ll in the path of the 0" tooth Is. At "0" position of the parts. "0 tooth II is below 0" nose end It so that shaft It makes almost a full revolution before the 0" tooth engages the coasting nose end It. Then during rise ofthe 0" key, the 0" nose end I! is withdrawn from the "0" tooth II and commo'n detent Ill moves between a pair of teeth I of disk III. Shaft It now rotates an additional amount until arrested by engagement of a tooth in with detent Ill. The total movement of the shaft will be through one complete revolution at the end of which the 0" stop finger It will again be in the position from which it started. correspondingly, item wheels OI meshed with drum OI will have moved through one revolution from 0" position to 0" position.

If with the parts in .0 position, the 1" key is depressed, then "1 lever II will be moved forward and common detent Ill" released from restraint on shaft ll. Shaft 10 will first rotate until the l finger ll engages 1" nose end It; then on the upstroke of the key, the shaft will be released for a further. slight, movement until arrested by detent IN. Similarly, depression of the other keys will cause movement of the shaft from "0" position through the number of positions indicated by the depressed key.

The reason for effecting part of the movement of the shaft upon the down stroke and the remainder of the movement upon the up stroke of the key is to correctly time the release and arrest of shaft I! by the oppositely moving nose end It and detent Ill and to provide clearance between detent its and teeth ill when the detent returns to restraining position.

lftheshaftltweretomovethecompletedifferential distance upon the down stroke of the ,key. at the end of this movement, a tooth I" would be exactly in line with detent Ill. Then when the active nose end It released the stop finger engaged therewith, shaft ll. might rotate slightly before detent Ill could move above the alined stop surface of the tooth I" in front of the detent. As a result. the detent would fail to engage the proper tooth Ill and shaft is would move an additional step. Further, if during return of the detent end IN, it were exactly in line with a tooth Ill, then it might strike the edge of the tooth and be unable to move above the tooth. By moving shaft I! through lessthan its full differential distance upon the down stroke of the key, detent m' can move with complete ciearness above the surface of the tooth Isl below it and the remainder of the differential movement can be conveniently effected to bring the tooth and detent into engagement.

When shaft It and item wheels 88 on drum II have been moved by depression of a key it to a differential position other than 0", the following key depression will not cause movement of the shaft and item wheels through the same number of steps as represented by the number on the latter key, but through such a number of steps as will bring the shaft and wheels to the diflerential position corresponding to the depressed key. For example. if shaft 1! is in "l" position, its "1 stop finger I. will be at the point initially occupied by the "0" finger. Now, ifa "1 key I! is depressed, shaft It will makes full rotation, in the same manner as descrlhd above in connection with the "0" setting, and under the successive control of the l nose end It and the common detent IN the shaft will again be in "1" position. i

If the shaft is in 1" position and a "2" key It is operated, then the shaft will move one mep before it is completely arrested and the "2" finger II will be in the position in which the "0 finger II is shown in Fig. 4. This latter position may be referred to as the reference position. If shaft It has finger It-l at the reference position. then depression of the 4" key II will cause movement of the shaft through six steps to bring the 4" finger It to the reference position. Similarly, no matter in what differential position shaft I! may be, depression of a key 1! will cause the shaft to move through the number of steps required to bring it to the position represented by the depressed key. Correspondingly, those item wheels It still meshed with drum ll will move from any diflerential position they occupy to the new position represented by the key last depressed. For example, if a wheel If on drum ll reads "4 and the 6 key ll is depressed, this wheel 80 will move two differential steps to read 6".

As explained above depression of a key diiferentially sets all the wheels I! meshing with drum II to the common position represented by the key. Thus, initially, all nine wheels are on the drum and operation of key Ii-4, for example, will set the nine wheels similarly. each to a "6 position.

In addition to setting wheels II, operation of any of keys ll controls an escapement mechanism to elect rotation of screw shaft as to an extent such as to move carriage II and wheels I! one step to the left, as viewed in Figs. 1 and 2, thereby removing one wheel 88 from drum II and meshing this wheel with the right hand end slide lac.

Referring particularly to Figs. 1 and 11, the escapement-controlled means for rotating screw shaft It comprises gear sector In pivoted on stud Ill carried by frame plate 01. A spring I22 connected to/sector III urges it clockwise (Fig. ii) to rotate gear train ill, III, I", and I". Gear I28 meshes with a pinion III fixed to screw shaft ll. Also meshed with gear I2. is a pinion Ill. (Figs. 1, 2. and 11) freely. rotatably, carried by shaft 1!. Rigid with pinion lll are two teeth I" and I" spaced apart along shaft II and having their radial. stop surfaces extending along the same diametral line and 180 apart.

Stop tooth I is normally in engagement with the nose end of a detent arm Ill rotatably carried by the left end of shaft 'II (see Fig. 1). Adiacent arm Iii, shaft II has rigidly fastened to it another detent arm I" located in the plane of tooth I. The nose end of arm It! is initially in front of. slightly below. and remote from stop tom-h I. A lug I" on arm I8! is held engaged with a stud iN'on arm III by a spring I" connected to the stud I and to the frame.

Referring to Fig. 4, when a key II is depremed tosetwheelsltltrockstheconnectedlever it which in turn rocks common bail ill clockleft side of bail III (as rection. ill from engagement with I.

The gear train comprising elements III, III, I, I", I", III, and m is now free to rotated by the power of spring I22. Pinion it. rotates a slight distance anticlockwise bringing its tooth III above and clear of the nose end of detent arm Iii and its tooth Ill into engagement with the top of detent arm ill. During this rotation of pinion ill, gear I" rotatu pinion ill and its shaft I through a small angle. causing movement of the item wheels ll on drum Ii slightly to the left (Figs. 1 and 2). but not to such an extent as to demesh the left hand one of the latter wheels from the drum.

The above, initial, mcape action of the wheels I! is the result of depression of a key ll. As previously explained, the depression of a key II also causes an initial setting operation to partially setthe wheelsaonthedrumtothereadingrepresented by the depressed key. During the, up stroke of a key, wheels 0 are given the final portion of the setting operation to complete their mtting to the differential position selected by the key. Also, during the upward, return. stroke of the key. the escapement means operates to effect a supplementary rotation of shaft II to complete the lateral step of movement of carriage 88 and wheels as. The completion of the setting of wheels I! overlaps the early portion of the supplementary escape movement of carriage I8 and takes place before the left hand wheel .3 meshed with drum ll has left the drum. In brief, the relation of the parts and their timing are such that upon the down stroke of a key. all but a minor portion of the setting movement of the item wheels is carried out while only a slight portion of the escape step is eifected, and upon the up stroke of the key, the slight, fractional, remainder of the wheel setting is com-.

pleted and the major portion of the escape step takes place.

Dm'ingtheriseofthekey.bail lll moves counterclockwise (Fig. 4), permitting spring I" to rock detent arm III to the left to position the nose end of the arm in the path of counterclockwise movement of associated stop tooth I" which atthistimeisabovethe noseofarm Ill due to the initial escape movement. when arm ill is rocked to the left (Fig. 11) by spring ill, through coaction of stud ill and lug I, arm I8! is similarly moved to the left, thereby withdrawing its nose end from engagement with tooth I. This leaves pinion Ill free to rotate coimterclockwise undertheinfiuenceofspring iltuntiltooth it.

engagesthenoseofarm ill. 'lhepartsofthe escape means are then in initial position, shown in Hg. 11 and pinion ill has completed a revolution. As a result of the supplementary. final. escape movement, gear III has rotated screw shaft it to complete the lateral step of movement of carriage N, and to thereby entirely remove from drum II. the left hand one of the group wbeelsltmeshedwiththedrumat thebeginning of the last key operation.

Inabovemanner,eachtimeakeyisoperated.

thesewheelsoifthedrumandontothefirstunits order, slide ilc. In nine key operations. wheels uwillbeniccmsivelydisplacedtotheleftuntil theyareallremovedfromllandinmmhwith nine sliihs Ila, t, and c. Similarly. one to ht key operations will move the same numberofwheels'jolldrumli andontothesame mnnberof II.

The reason for electing the escapement movement in two parts and under control of two deminste. If only one detent and escapement tooth were provided, there would be no assurance that the detent after release by the depression of the key wouldberestoredintimetoarrestthe tooth when it had made one revolution. By utilising the two detents Ill and ill. at least one is always in position to engage the coacting tooth ill or I and regardless of the length of time during which a key is held down, the mcapement mechanism will move (lily one full step for each reciprocation of a key.

As an example of the setting and mcape operations. assume the price of an article is 8.50, the kind of sale is charge send represented by code number 4. and that the clerk's number k 11. Initially shaft I! is in "0" position and the nine wheelsllareondrumti. 'Iheoperatorfirst depresses key "-4, causing release of detent end Ill of lever I from disk-ill. Shaft ll moves ahnost eight difierential steps from its "0" puition until arrested by engagement of stop finger IQ-I with the nose end of the vertical arm of lever1l-4.anddrumllandtheninewheelsll move synchronously with shaft It. Depression of key Id-8 also earned release of detent iii from tooth I" of pinion I", and simultaneously caused movement of detent ill into the path of movement of tooth I of the pinion. Spring I it acts, upon release of pinion III, to rotate the latter a slight amount until tooth Ill engages detent I82. This initial rotation of pinion III is accompanied by corresponding rotational movements of gear III and pinion ifl. Shaft I. of the latter pinion coacts with carriage N to shift the latter and the nine wheels 08 slightly to the left.

when the operator releases key "-4, lever lll rocks counterclockwise (Pig. 4), withdrawing its nose end from stop finger ll-l; simultaneously spring ill moves detent end ill above a tooth i of disk ilf. Shaft ll rotates a sllsht amount. completing its eight step movement from 0" position, and is then arrested by engagement of the detent end ill with the tooth III. During the latter rotation of shaft ,Il, the nine wheehuondrumli arecorrespondinglyrotated and now set to read "s".

"8" through sight opening 44 (Fig. 23).

During rise of key Ii-J, detent I42 is displaced from tooth I30 of pinion I24, and detent I2I is interposed in the path of rotation of tooth I24 of this pinion. Spring I22 acts now to rotate pinion I24 through the greater part of a revolution until tooth I28 engages detent Ill, and the pinion.

wheel 43 from the left (Figs. 1 and 2) moves drum 4| and onto unit slide I40. At the end of the escapement step, this first. wheel 44 reads The other eight wheels are still on the drum.

The clerk now depresses key Ii-4; shaft I4 rotates from its 8" setting an amount just short of seven steps before being arrested by engagement of stop finger II-J with lever 1H. Upon the up stroke of the key, shaft It covers the remaining distance to its "5" position where it is arrested by detent I44.

The eight wheels which at the beginning of the operation of key II-4 were on drum II are set now at "5". The reciprocation of the key effected escape of the carriage 44, bringing the left hand one of the latter eight wheels off drum II and onto unit slide I4c, where its reading "5" is visible through window 44. The left hand one of all nine wheels 42 had been set duringthe first key operation to "8" and demeshed from drum 4i, so that it was not afiected by the rotation of drum 4| whichtook place upon the secondkey operation and remains at "8". The second escape operation of carriage 44 moves the latter wheel 44 onto the tens order slide IIc which is the second one from the right (as viewed in Fig. i.)

In the same manner. keys I4 are successively depressed to set up 0.. 4. and 11 on wheels 44. At the end of the six required key operations, the first wheel from the left will read 8,-and be in mesh with units dollar order slide I40, the next wheel will read 5 and mesh with dimes order slide Ila, the third wheel will read 0 and mesh with the cents slide Its, the fourth wheel will stand'at 4 and mesh with transaction slide I4t, and the fifth and sixth wheels will each read 1 and be lnmesh with tens and units slides IIIc. Through sight window 44, the reading 850 will appear under a suitable heading (not shown) denoting "amount", '4' will appear under a heading (not shown) denoting "kind of sale", and "11" will appear below a heading (not shown) indicating "clerk."

The last three wheels 44 will remain on drum 4I each wheel reading 1" as a result of the last key setting: .Also, the last three higher order slides Ila, namely,the thousands, hundreds, and tens of dollar orders slides will be out of mesh with any of wheels 43. The abutment "provided on carriage 88 will be in front of these last three slides Ito, as has been explained before.

During the cycle of shaft 44, which is initiated bythe operator subsequent to the setting operations, the item wheels. remaining on drum II are set to 0". For this purpose, a gear I34 at the right end of cam shaft 49 (as viewed in Figs. 1 and 3) carries at one side a cam piece I41 (see also Fig. During the initial portion of revolution of shaft 44, cam piece I4'l rides past the free end of an arm I44 fixed to one end of a shaft I48, and thereby rocks shaft I34 clockwise (Fig. 10) The opposite end of shaft I44 has fast to it an upright arm I44 connected by a link I to an arm I42 loosely mounted on shaft 11 (see Figs. 4 and 16). Arm I42 is in the same vertical plane as a special zero stop finger I4'Il secured to shaft 14 at the left of the ten-key controlled fingers I4 and disposed in the same relation to arm I42 as that of the key-controlled 0" finger 14 to nose end 16' of "0" lever III. Arm I42 has a lug I44 held engaged with pin I44 on detent arm I04 by spring I45.

when cam lug Iflrrocks shaft I24 clockwise, the shaft, through armv I44 and link I4I,rocks arm I42 in the same direction. Arm I42, through .eoaction of lug I44 and stud I44, displaces detent I44 from the teeth ill of disk I42,,permitting spring 44 (Fig. 7) torotate gear drum 4i and the item wheels 84 thereon until special 0" finger I4'-4 abuts the nose end of arm I42.

Cam piece I81 holds arm I44 depressed long enough for shaft "I4 to make substantially one revolution. When the cam lug rides oi! the end of arm I44, then spring I45 restores detent arm I44 which in turn restores arm I42. Arm I42 thereupon releases finger I4 and shaft I4 completes its movement to "0 position, where it is stopped by detent I44 engaging a tooth I44 of disk I42. Shaft 14, drum 4|, and the item wheels 44 on the drum are now at 0" positions. 7

Subsequent to the above described setting of the wheels on drum II to 0", the spring actuator 44 of drum 4| is retensioned. This is done by a cam I44 (see Figs. 1, 3. and 'I) fastto cam shaft 44. During the revolution of shaft 34, cam I45 acts on roller I44 of gear sector 44 to rock the sector counterclockwise, thereby retensioning spring 44. As sector 44 moves counterclockwise through gears 41 and 44, it rotates pinion 42 and its shaft 42 in the same direction. During the counterclockwise revolutions of shaft 42, arm 49 on the shaft rides over pawl IIIII without restraint due to yielding of spring I04. Any tendency of drum 4| to rotate counterclockwise during such movement of shaft 42 is effectively prevented for thmfollowing reasons:

counterclockwise motion of drum .4I would,

rotate shaft I4 clockwise (Fl!- 7) and. the latter movement would be effectively stopped by ensagement of the top of detent end I44 with the I44 directly above it (see Fig. 16) before shaft I4, could move one diii'erential step. Furthenifanyitemwheelsltarestiilondmm 4|, they are at zero positions and would also prevent tendency of the drum to rotate counterclockwise. This is because each wheel 43 has a home 'or zero position dog I44 (see Fig. 6a) which when the wheel is in zero position, is engaged with a fiat shoulder I44 formed alongshaft 4Iofthewheels(seealsol"lg.l).

For drum II to rotate counterclockwise requires clockwise movement of the wheels "on the drum, which are now at 0" position and cannot move clockwise because of dogs I44 abutting shoulder I44 of shaft 44. As a result, drum 4| cannot move counterclockwise. Nor can the drum move clockwise, unless released by disengagement of detent I44 from teeth I44 of disk I42, which occurs only under control of keys II or can Il'l.

Drumll hasthreetimesasmanyteethasan item wheel 44 and when the latter is in 0" position, pawl III. on the drum may be in either of three "0" positions, the one shown in Fig. I, and 

